Diodes generally function as an electronic version of a one-way valve. By restricting the direction of movement of charge carriers, it allows an electric current to flow in one direction, but blocks it in the other direction. Diodes can be used in, for example, radio demodulation, logic gates, power conversion, and over-voltage protection. Most modern diodes are based on semi-conductor p-n junctions. In a p-n diode, conventional current can flow from the p-doped side (the anode) to the n-doped side (the cathode), but not in the opposite direction. When the diode is reverse-biased, the charge carriers are pulled away from the center of the device, creating a depletion region.
A need exists to provide diodes which have improved performance characteristics. One approach which can be used is use of organic semiconducting materials including polymeric materials such as conducting polymers, or conjugated polymers, to tune the diode properties. However, some conducting polymers do not provide suitable processability and purity for device applications including diodes and are difficult to fabricate into thin films. Higher conductivity and tunability can be lacking in many materials.
In particular, improvements are needed in use of conducting polymers in diodes which are not light emitting diodes. Improvements are also needed in diodes which are not designed to be part of a photovoltaic cell.